Performance – IT Blog

Messages net_ratelimit: X callbacks suppressed

Once I found the following messages in the dmesg log:

Script to bind Intel NIC interrupts to processor cores

I will give the script code from Intel to bind interrupts of Intel network adapters to processor cores, and also show examples of its use:

Taskset – bind process to CPU cores

By default, processes use all the processor cores, but sometimes it is necessary to release the 0 core, which is usually the most loaded, or assign some processes only to the second CPU, etc., in this case, taskset will help.

Increase the port range net.ipv4.ip_local_port_range

There is a possibility that on a highly loaded server, such as a proxy or router, with a very large number of connections, free ports in the allocated range may run out, so you need to look at the current number used and, if necessary, increase the net.ipv4.ip_local_port_range value.

Configuring logrotate to rotate logs

Logrotate is used to control the logging system, compress log files, delete old ones, etc.
The configuration is located at /etc/logrotate.d/ and /etc/logrotate.conf.

Testing a DHCP server with dhcpperf

dhcpperf is a DHCP load testing tool.

How to change innodb_flush_method in MySQL

innodb_flush_method defines the method for flushing data from RAM to disk.

High CPU load on Cisco Nexus 3064

Once I discovered on the graphs a large burst of Multicast packets on one of the ports of the Cisco Nexus 3064 switch, while the CPU load increased to 30%, before that it was 12% with L2 traffic of 13 Gbit/s.

Migrating MySQL Directory

Once I created a raid, mounted it as a disk system partition and transferred the MySQL directory directly to it, but in this case there were drawbacks, the lost+found directory could appear, it could not be used for other data, etc., after that I began to transfer the MySQL directory not directly to the partition, but created a directory on it and transferred it to it.

How to change innodb_io_capacity in MySQL

innodb_io_capacity – determines the number of write IOPS for background InnoDB tasks, such as flushing pages from a buffer pool, etc. If the cleanup operation is lagging, then InnoDB can perform cleanup more aggressively at a higher IOPS, which is defined in the innodb_io_capacity_max variable.